The present invention relates to a flat-face quick coupling.
Flat-face quick couplings, comprising a male element which can be coupled to a female element are already known in the prior art.
Said prior quick couplings are used in several field and, in particular, for coupling working assemblies, driven by a pressurized hydraulic fluid, to an apparatus provided for supplying the pressurized hydraulic fluid.
A typical field use of the above mentioned flat-face quick couplings is, for example, that of agricultural machines, or specially devised machines for making or servicing roads.
For example, in the agricultural machine fields, the mentioned quick couplings are used for coupling auxiliary equipment to a towing vehicle, such as a tractor.
Prior flat-face quick couplings have been found as very useful and operatively efficient, mainly due to the fact that, as they are clutched, no undesired oil leakage occurs, and, accordingly, the environment is not polluted thereby.
However, a drawback of said prior flat-face quick couplings is that they, because of their lacking of any oil leakages, do not allow to fully reduce the oil pressure inside the coupling: thus, it is not possible to connect two quick couplings as remaining inner pressures are still present in the hydraulic system.
Therefore, the devices receiving the flat-face quick couplings are considered by a user as defective or failed.
Consequently, the user frequently attempts to connect the two devices including the mentioned flat-face quick couplings by applying comparatively large forces which could seriously damage said couplings, with a consequent leakage of the hydraulic fluid.
Accordingly, the aim of the present invention is to provide an improved flat-face quick coupling which can be clutched without any oil leakages and without the need of overcoming remaining pressures inside said quick coupling.
According to one aspect of the present invention the above mentioned aim is achieved by a flat-face quick coupling, comprising an outer tubular body and a bushing threaded in the tubular body for receiving, in an axially displaceable manner, a tubular element coupled, in a per se known way, to means for providing a flat-face quick coupling, by providing that the tubular element is rigid with a tubular body which, on an outer circumference thereof, comprises sealing ring elements, that through a body of tubular element a throughgoing hole is formed, which, through a cross hole communicates with a chamber of the quick coupling, that the throughgoing hole has a valve seat which can be shut-off by a valve stem preloaded by a spring, that the valve stem comprises an extension projecting into a chamber formed between the tubular body and tubular body, and that from the chamber extends a throughgoing hole connected to a discharging fitting.
Thus, by using such a quick coupling it is possible, by actuating a tubular element of the coupling, to open the outlet valve provided inside the coupling, thereby fully discharging the hydraulic fluid while fully eliminating residual or remaining pressures inside the coupling.